The nmnerieal aperurc (NA3 of the double beam thterferometers (DBD can affect the acotrate measurement of surface profiles. Based on the double beam interference microscope imaging theory, the fringe spacing will vary wide nonlinearly with the increasing of numerical aperture. The double beam interferometers require oblique incidence illmnination, including Miehelson, Mirth and Linnik lypes. The intensity distribution of the ilumination across its slop is constant so the correction factor depends mainly on the NA in the Michelson and Linnik interferometers. The correction factor expression is derived in the Miehelson interferometer. The reference surface is a central obscnration in the beam, which will reduec the effective mnnerical aperture in the Miran interferometer. At the same mumerical aperatre, larger central obscuration has a much effect on the correction factor. The correction factor expression is determined by considering the influence of central obseuration and oblique incidence in the Mirau interferometer.

A new structure for bit synchronization in a tera-bit/s optical interconnection network has been designed using micro-electro-mechanical system (MEMS) technique. Link multiplexing has been adopted to reduce data packet communication latency. To eliminate link set-up time, adjustable optical delay lines (AODLs) have been adopted to shift the phases of the distributed optical clock signals for bit synchronization. By changing the optical path distance of the optical clock signal, the phase of the clock signal can be shifted at a very high resolution. A phase-shift resolution of 0.1ps can be easily achieved with 30-μm alternation of the optical path length in vacuum.

In this paper, we present a low cost fiber-optic data link for the computing cluster. The link is a 32bd-virtual channel fiber-optic computer bus used only a pair of OE devices and fbers The link is integrated with the popular PCI Bus interface in order to make the link hold the same bandwidth as that of the PCI Bus. and it can operate under managed by PCI Bus. Our research addresses how to match accessing bandwidth between computer bus and high-speed optical interconnection, and how to make low overhead and latency interfaces between optics and electronics, and integrates fiber optic link into computing system designs.

基于白光干涉原理，通过麦克尔逊干涉仪的光程补偿作用，检测保偏光纤空间分布寄生偏振耦舍强度和耦合点位置。经数据采样时域理论分析知：扫描步长增大时，耦合强度检测误差和耦合点位置判断误差呈线性增大。扫描步长小于500nm时，强度误差小于5%，位置误差在±11mm之内。

This paper presented an optical intercormection multiple PC system connected by a ring network. This multiple PC system uses Linux Operating system, and the standard communication protocol of complying with Ethemet specification This paper studied the factors that influence the intereomection performance among multiple computers, including the effect of the buffer size of OLI on the bandwidth of network layer, and the effect of retransmission method on the performance. The results of ping-pong test show that optical fiber link is able to provide high-bandwidth and low-latency communication for a multi-PCs system. We found that the performance of the interoonneetion network can be improved by improving the interface match between the optical fiber link and computer bus input/oatput. Besides, the development of a chip to implement network interface and a part of network protocol, such as developing with FPGA device in this paper, could result in the higher performance of the interconnection.